Solar panels system with MPPT controller and Battery system (www.elprocus.com)
The origins of solar power date back to the mid-1800s when French physicist Edmond Becquerel discovered the photovoltaic effect - the ability of certain materials to generate electricity when exposed to light. This groundbreaking finding paved the way for Charles Fritts' invention of the world's first solar cell in 1883.
Fritts' primitive solar device kicked off further innovations that gradually made solar energy more practical and efficient. By the late 20th century, advancements in materials science and manufacturing enabled today's highly refined photovoltaic panels. Modern solar arrays possess vastly improved capabilities compared to early prototypes.
Solar technology has now reached a point where panels can reliably power everything from pocket calculators to entire homes or facilities. They even generate electricity on spacecraft exploring the far reaches of our solar system. What started as a scientific curiosity observed by Becquerel has blossomed into a versatile renewable energy solution applied across diverse settings both on and off Earth. Continuing refinements signal Solar's bright future as a leading clean power source.
Solar panels in space (www.theecoexperts.co.uk)
HOW A SOLAR PANEL WORKS
At their core, solar panels utilize the photovoltaic effect to convert sunlight into electricity through a process that begins at the level of semiconductors. The key components are layers of N-type and P-type semiconductor materials, which form a junction where they meet.
Conductive plates are applied to each side of the N and P layers. Wires connect these plates to output terminals where power is drawn off. When sunlight falls on the solar cell, photons are absorbed in the semiconductor material. This gives energy to electrons, allowing them to break free from their atoms.
The electrons are able to flow easily in the N-layer but not in the P-layer. At the junction, electrons from the N-layer flow into the P-layer, creating an imbalance of electric charge on either side of the junction. This separation of charges establishes an electric field that pulls electrons that migrate through an external load back to the P-layer, generating a flow of current and providing usable electricity. In essence, the solar cell acts like a battery that replenishes itself as long as the sun shines.
solar power plant construction and working (https://medium.com/)
At the junction where the N-type and P-type layers meet, electrons from the N-layer bond with "holes" in the P-layer, thus filling them. This binding of electrons and holes establishes a charge layer at the junction. In this initial state before exposure to sunlight, there is no movement of electrons or flow of current.
However, when photons from sunlight hit the junction, they impart energy that breaks the bonds between electrons and holes. The electrons and holes are dislodged back into their respective N-type and P-type layers. Because these layers are doped differently, the electrons want to flow towards the P-layer and the holes to the N-layer.
If metal terminals are affixed to each side and connected to an external circuit, the electrons will seek to flow through the circuit to recombine with the holes. This movement of electrons—from the N-layer terminal, through the external circuit, to the P-layer terminal—constitutes an electric current. So by harnessing the photovoltaic effect, the junction generates current when exposed to sunlight.
Building a DIY Solar Battery Charger
In this DIY project, we'll construct a portable solar charger capable of supplying power to any 5V USB devices, such as cell phones, tablets, or Arduino circuits. This photovoltaic charger harnesses the sun's energy to remotely energize your electronics.
Assembling the Circuit (https://www.circuitbasics.com/)
For this solar charger, we'll use two 3.7V lithium-ion batteries connected in parallel. Each has a capacity of 2600mAh, providing a total of 5200mAh.
A TP4056 module will safely charge the batteries. It regulates input from 4.5-6V and outputs to the proper voltage level.
We selected a 6V, 4.5W solar panel that delivers around 750mA at 6V. Assuming 85% efficiency, that's 640mA available to charge.
Given the 5200mAh capacity and 640mA charge rate, basic math shows it will require approximately 8 hours of sunlight to fully recharge the batteries.
Since the batteries are 3.7V but USB devices need 5V, a step-up converter boosts the voltage. However, its 2A maximum exceeds the 1A limit of the TP4056 charger module.
So while this setup works for low-power uses, high-drain devices could overload the charger module. We must stay within its 1A rating during operation to avoid potential issues.
Proper component matching, calculations, and attention to current/voltage specs ensure this solar charger charges and runs safely.
Here’s the completed circuit:
The solar panel connects to the circuit board via two wires - red and black. As is standard, the red wire delivers positive voltage while the black is negative ground.
There is also a small slide switch located towards the top right corner of the board. Flicking this switch to the off position cuts power from the solar panel, allowing the charger module to be disabled when not in use.
This switch provides a convenient way to stop the flow of current entering the board, such as at night when the panel is not exposed to light. It helps prevent minor power drain when the charger sits idle for extended times.
Scaling Up Solar: Large Installations for Powering Buildings and Industry
Our DIY solar charger showed how small panels can power portable devices. But what if we want to harness more sunlight? Larger solar installations can supply homes or bigger builds.
Solar panels connect in series to boost voltage safely. When placed end-to-end, the voltage outputs accumulate rather than pile up amperage uncontrollably.
For example, hooking three 12V panels in series yields 36V total - ideal for operating DC appliances directly without conversion losses. Or connecting enough panels to reach mains voltage allows solar-generated AC through an inverter.
solar panels connected in series, the voltage of each panel adds up to a higher voltage (https://www.circuitbasics.com/)
Connecting solar panels in parallel keeps the voltage the same while increasing total current output(https://www.circuitbasics.com/)
It's evident that creative arrangements of series and parallel connections yield desired voltage and current specs. Just as with our solar charger, maximum ratings for all components like charge controllers and batteries must align.
Optimal configurations extract full potential while respecting safety limits. Careful planning leads to robust, harmonious systems channeling the sun's free energy where most needed—whether charging a portable device or illuminating an entire home. With Solar's flexibility, the opportunities are limited only by one's imagination!
Sizing Up Your Solar Needs: A Guide to Calculating Optimal Panel Output
Let's say we want to add solar to a vacation cottage. First up, we need to estimate daily energy usage. Make a list of all appliances and rate each in watts. Then determine average hours used per day.
Now calculate watt-hours for each with this formula: Watts x Hours Used. For example, a 500W refrigerator running 12 hours yields 6,000 watt-hours.
We'll inflate this 30% to account for losses. So 6,000 watt-hours becomes 7,800 after multiplying by 1.3.
Look up the average daily sunlight hours for your location online. Next, divide the daily watt-hours by sun hours to get required panel watts.
With our 7,800 watt-hours and 5 sun hours, the math is 7,800 / 5 = 1,560 watts. So we'd need a 1,560W panel. Or multiple 100W panels - around 16 in this case.
Feel free to drop a comment if any part of the process remains unclear - I'm happy to clarify or expand on steps. Wishing you the best in designing renewable energy solutions customized for your location and energy goals. Don't hesitate to reach out as you embark on your own solar journey.
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